MOLECULAR MECHANISMS OF ESTROGENS VASCULAR ACTIONS

雌激素血管作用的分子机制

• 批准号: 6390329
• 负责人: KENNETH E CLARK
• 金额: $ 37.96万
• 依托单位: UNIVERSITY OF CINCINNATI
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-08-01 至 2004-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6390329
• 关键词: estradiol; estrogen receptors; estrogens; hemodynamics; hormone regulation /control mechanism; nitric oxide; nitric oxide synthase; protein isoforms; protein protein interaction; sheep; uterus; vasodilation

Although the uterine vascular effects of estrogen have been studied for over 70 years, the mechanism by which estrogen produces vasodilation remains unclear. Our laboratory was the first to show that a significant component of the uterine response to estrogen in the nonpregnant sheep is mediated by the release of nitric oxide (NO). We and others have shown that estradiol-17beta increases the expression and activity of endothelial nitric oxide synthase (eNOS) in the uterine circulation. However, it is not currently clear how this occurs or if, in addition to eNOS, neuronal nitric oxide synthase (nNOS) or inducible nitric oxide synthase (iNOS) are also important in maintaining the sustained vasodilatory response seen after estrogen administration. Furthermore, it is not clear how estrogen modulates these NOS isoforms at the cellular and molecular level. Recently a new estrogen receptor, ERbeta has been isolated and emerging data suggest that this receptor may mediate a significant portion of the effects of estrogen in the vasculature. We hypothesize that uterine vasodilation produced by estradiol-17beta is mediated by specific interaction with both ERalpha and ERbeta, which subsequently activates eNOS (and potentially nNOS) via a nongenomic pathway, and iNOS via a genomic pathway, leading to increases in NO. The present application plans to evaluate the role of ER as a modulator of the NOS isoforms in the uterine circulation using a combination of physiologic and molecular endpoints. We will monitor the uterine hemodynamic responses to locally and systemically administered pharmacological antagonists that are selective for specific isoforms of NOS using a well-characterized ovine model. We intend to evaluate the expression of ERalpha and ERbeta in the ovine uterine vasculature and explore how estrogen alters eNOS, nNOS and NOS expression in endothelial cells and vascular smooth muscle. Finally we plan to determine if endogenous estrogen, acting through the uterine vascular NOS system, plays a critical role in increasing and maintaining uterine blood flow in late pregnancy. We believe that the information obtained in this revised application will provide new and important understanding into the mechanisms regulating vascular tone and hemodynamics in the uterine circulation in both the nonpregnant and pregnant animal.

尽管人们对雌激素对子宫血管作用的研究已有 70 多年的历史，但雌激素产生血管舒张作用的机制仍不清楚。 我们的实验室首次证明，未怀孕绵羊子宫对雌激素的反应的一个重要组成部分是由一氧化氮 (NO) 的释放介导的。 我们和其他人已经证明，雌二醇-17β 可以增加子宫循环中内皮型一氧化氮合酶 (eNOS) 的表达和活性。 然而，目前尚不清楚这是如何发生的，或者除了 eNOS 之外，神经元一氧化氮合酶 (nNOS) 或诱导型一氧化氮合酶 (iNOS) 是否对于维持雌激素给药后出现的持续血管舒张反应也很重要。 此外，尚不清楚雌激素如何在细胞和分子水平上调节这些 NOS 亚型。 最近，一种新的雌激素受体 ERbeta 被分离出来，新出现的数据表明，这种受体可能介导雌激素在脉管系统中的大部分作用。 我们假设雌二醇-17β 产生的子宫血管舒张是通过与 ERα 和 ERβ 的特异性相互作用介导的，随后通过非基因组途径激活 eNOS（以及潜在的 nNOS），并通过基因组途径激活 iNOS，导致 NO 增加。 本申请计划结合生理和分子终点来评估 ER 作为子宫循环中 NOS 亚型调节剂的作用。 我们将使用特征良好的绵羊模型监测子宫血流动力学对局部和全身施用的药理拮抗剂的反应，这些药理拮抗剂对 NOS 的特定亚型具有选择性。我们打算评估绵羊子宫血管系统中 ERα 和 ERβ 的表达，并探讨雌激素如何改变内皮细胞和血管平滑肌中 eNOS、nNOS 和 NOS 的表达。 最后，我们计划确定内源性雌激素是否通过子宫血管 NOS 系统发挥作用，在妊娠晚期增加和维持子宫血流量中发挥关键作用。 我们相信，在此修订的申请中获得的信息将为调节非怀孕和怀孕动物子宫循环中血管张力和血流动力学的机制提供新的重要理解。